1. Field of the Invention
The field relates to an electromagnetic actuator, in particular for valve arrangements, having a coil arrangement which can be excited electrically, having an armature which is mounted such that it can move axially in the coil arrangement, being composed of soft magnetic material and is moved in the axial direction when the coil arrangement is excited, and having a guide sleeve, which is fixed in the coil arrangement and guides the armature in the axial direction.
Furthermore, the field relates to an operating arrangement for operation of a valve arrangement, having a valve control element which can be moved with a linear actuator in an axial direction between a first actuating position and a second actuating position, in particular with an electromagnetic actuator as described above.
2. Description of the Related Art
An electromagnetic actuator of the type described above is in general also referred to as a switching magnet and is disclosed, for example, in “Kraftfahrtechnisches Taschenbuch” [Automotive Handbook], BOSCH, 25th Edition, 2003, pages 142, 143.
In electromagnetic actuators such as these, a working air gap is formed between the armature and a core (which may be part of a magnetic return-path device). When the coil arrangement is excited, a force is exerted on the armature, depending on the length of the working air gap. The characteristic force/distance characteristic generally behaves in accordance with a square law over the actuating movement.
The armature is in general guided by a separate guide sleeve, which is designed to be non-magnetic, within the coil arrangement. The gap which is generally in the form of an annular gap between the armature and the magnetic return path device also has a significant influence on the effectiveness or the efficiency of the switching magnet. If a non-magnetic guide sleeve is arranged in the clearance air gap, the magnetic characteristics become worse.
In the case of operating arrangements for operation of a valve arrangement, it is on the one hand possible to directly couple a valve control element to a valve slide.
However, valve arrangements also exist in which a valve control lever can be pivoted between a first valve position (first sealing position) and a second valve position (second sealing position).
During operation of valve arrangements such as these, it is particularly difficult to match the actuating movement of the linear actuator that is used to move the lever between the first and the second valve position.
Furthermore, one situation that frequently arises with valve arrangements such as these is that sealing elements for the valve control lever are plastically deformed over time by the valve seat. This results in the sealing effect deteriorating over the course of time.